Credit card reader for sensing density of resilient material

ABSTRACT

Methodology and apparatus for sensing embossed numbers on such articles as credit cards and the like. The sensing is accomplished by a resilient pad having a uniform density of suspended material or an embedded layer of material which is either conductive, magnetic, reflective or radioactive and sensors behind the resilient pad which are sensitive to the substance of the material and fulfill their recognition upon the embossed numbers compressing the resilient pad and increasing the conductive, magnetic, reflective or radioactive density in the area of the embossments only.

United Stat 1 3,596,249

[72) Inventor Wuhae... no References Cited MkflgNX. UNITED STATES PATENTS 25:; 3,40l,830 9/1968 Mathews 235/617 B [45] Patented III] 37, 1971 Primary Examiner-Harold l. Pitts [731 Assignee Texaco he. Attorneys-Thomas H. Whaley and Carl G. Ries N" York, NY.

ABSTRACT: Methodology and apparatus for sensing embossed numbers on such articles as credit cards and the like. The sensing is accomplished by a resilient pad having a [54] CREDIT CARD READER FOR SENSING DENSITY ":22? uniform density of suspended material or an embedded layer of material which is either conductive, magnetic, reflective or [52] US. Cl. 340/149, radioactive and sensors behind the resilient pad which are sen- 340/147 sitive to the substance of the material and fulfill their recogni- [51] Int. Cl- H04q 3/00 tion upon the embossed numbers compressing the resilient [50] I'leU at 58c! 340/ 149, pad and increasing the conductive, magnetic, reflective or 149 A radioactive density in the area of the embossments only.

PATENTEB JUL2 7 as?! SHEET 2 [IF 4 wo N w kw m6 mu wo' fi aw Q0 7 Nu Noll: fl w, QN (Q 7 R Olllll NNQQ we M QR Q u N m mum {8w NM NR REY a \n0 Q @m PATENTED JUL27|97| SHEET u m 4 z lmsm am CREDITCAIDR'EADER FOR SEX SING DENSITY F IESILIENT MATERIAL aacxoaouuoor rue INVENTION This invention pertainsvin: general; to character recognition apparatus; and, more particularly. to reading characters, or numbers, on such articlesaslcreditcards andthe like.

Although. the invention. is hereinafter described, andillns trated; in the accompanying drawing'figures, as'beingusefulin optically, magnetically, conductiyely.- or radioactively. reading anidentification number embossedina credit card it isto be understood that the" inventionfsa use is. not: limited to these specific types of reading of; credit. card numbers. Nor is it limited-to reading numberswhiclr-are embossedlor etched on a credit card 'since depressions canid'o aswell, although the'invention has particular, advantages when used inthe way described.

One widely used form of creditzcard construction is the relatively thin plastic card whi'chameasuresaboutxZifiinches by 3% inches. The card-bears'an identify-ingnumber (e;g, lOd'ecimal digits) \vhich'is embossed by meansofa dieinto the card 7s sur-- face. More particularly, the embossing or etching operation: raises the digits upwardly-on: one face. of the cardl Usually there is a substantial amount:ofi'printedYmatter on either-'Or-' both faces of the card. The-creditacard constructionhereinbe-- fore succinctly and generallydescribedis-notentirely-satisfactory for'some methods of'character. recognition or reading;

SUMMARY; OE THE VENTION" radioactive characteristics in a resilient pad to readidentifica tion characters, such as decimal digits,- on an article'suchas a credit card.

Anotherobjectof the presentainvention is to achievethe the credit card on the pad, are directed through a suitable lens and projected on to amask. The mask includes for each em bossed digit, or -character, a unique" pattern, or array, of apertures, or'holes, which permit thereflected light to: illuminate some phot'odetectors associated with the holes in said array and not illuminate other photodetector's associated with other holes in said array. The illuminatedand nonilluminated photod'etectorsare instrumental in gerieratinga set of signals which are representative of theilig ht projected from the particulardigit tobe recognized or" read;" Fin a'lly,setsof such signals representing all the charactersof the car'ds identification or account number are'trans'ferred toa comparator unit which: compares, in effect, the cards characters with charac ters stored in a" suitable'memoryunit or medium in order to establish whether a like setof characters representing a particularidentification'number, exists in the memory unitl It should be-also-noted that when=the conductivity of the suspendedmaterial; reactance of the'magnetic material'or activity of' theradioactive material respectively of the increased density of conducting, magnetic, or radioactive material, respectively, resultingfrom the pressingof the embossed'portionsof the credit card on'the' pad'do not'requireprojection onto a mask'but instead'respectivesensorscapable of sensing the'increased density of the material-in-question are fixedat pointsbehind the pad in' accordance with a" predetermined unique-pattern'orarrayof points'wh'ich permifthe sensors to distinguisii' tlie'particular character or characters on the credit card by nie level of medium recognized by the sensors. The sensors are'biased ata particular level which can differentiate between-an increased densityorrelative proximity of material in thepad 'adjacentto' the sensor so that the sensor is eitheractivated'or not-activated by an increaseddensity or mainforegoing objectiveswith respect to. articles, such as credit card readers using credit cards: ofthekind herein'before generally described, which have identification characters, such as decimal digits, which'aretembossed .or etched -in-said article, or credit card.

STATEMENT OF THE INVENTION I Thus, in accordancewith theillustrative, not limiting,- embodiment of the invention, thereis provided-amethod of verifyingthe-credit of a particular account wherein the'account is evidencedby presentation of :a'.cr edit cardz havinglhereon a plurality of embossed marks representing said account identification number comprisingpressing at least one of said marks against a resilient padhaving a uniform layer-or a uniform-depression of suspended'inaterial therein'in a reader,

sensing at a predeterminedgroupgof points in conformity with a preestablished code, the density level of thesuspended material at each of thexpointsz -in 'the. area-of the :pad compressed by eachof the marks, generating setsiof signalsat each group of points in response to the-sensing of-the density level, each generated set of signals-being representative of anindividual one. of the marks, encoding ,each set of generated signals in binary signal form, andcomparing the binary signals withother binary signals representingst'ored credit card-account numbers in order to verifjithe credit of the accountv represented by the marks on the credit-card.

Note that light. reflectedwfromthe increased density'of reflective materialof the proximity of theembedded layer raised as a result'of the pressing of-the embossed portions of tenance of the uniform density in the area adjacent thesensors respectively. The activated 'and nonactivated'sensorsare instrumental in generating-a set of signals which are representative" of the medium" activity from the particular character or mark o'rdigit tdbe recognized 'or readf Moreover, in the case of account validation, for example, sets-of such signals representing-all the characters'of the card's identification or account number-are transferred toa comparator unitwhich compares in the same manner asthc signal ge nerated' by phfdtodtectors from'reflective'material.

If, for'ex'ample, delinquent account numbers are stored in the memory unit and one such number corresponds with the 'number'on'thecreditcard, thenappropriate action may be taken;

Other objects as well as the various features and advantages of theinventi'on'appearhereinafter where specific illustrative "embodimentsof thevario'us features of the invention are set forth anddescrib ed in detail with reference to the accompany ing drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG." [is a diagrammatic illustration including block diagrams of the overall system according to the invention.

FIG. 2 is a frontal view'of a typical credit card having an identification number thereon.

FIG. 3'is a cross-sectional view through the credit card shown in FIG. 2, taken along the section line 3-3 therein with the identificationnumber shown embossed thereon.

FIG. Ba is a cross-sectional view through the credit card shown in FlG.2,' taken along the section line 3-3 therein with the identification number shown etched thereon.

FIG. 7 is a diagrammatic illustrationof an alternative system to that shown in FIG. I and employing optical fibers to transmit reflected light to the apertured mask.

FIG. 8 is a partial sectional view of the position of the pad with embossed credit card of FIGURE 3 disposed in reading position pressing against the pad.

FIG. 9 is a partial sectional view of the position of the pad which is an alternate embodiment having a resilient sheet for distortion by the embossed credit card of FIG. 3 when in reading position pressing against the pad. 7

FIG. 10 is a partial sectional view of an alternate embodiment of a pad having a fluid in the center of the pad and a be]- lowed reservoir in communication with the inside of the pad.

FIG. 11 shows the embodiment of the padof FIG. 10 with an embossed credit card of FIG. 3 disposed in reading position pressing against the face of the pad and the bellowed reservoir enlarged by the fluid pressed out from the center of the hollow pad.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A series of sensors 22a...22j are spaced adjacent the resilient pad 15 and are responsive to a concentration of measurable quantity as a result of compression of the mat of material compressed by the credit card. Such sensors (22...22j) can be detectors of, for example, magnetic or inductive fields of flux, higher reflectivity differing concentrations of light and/r varying concentrations of radioactivity as a result of distortion, diffraction or interference patterns or radioactive material concentration in the compressible mat. The sensors 22a...22j can be placed in an area array such as shown in FIG. or in a line perpendicular to the embossed line of figures on the credit card. This line of sensors is then moved relative to the card or vice versa with the travel being measured in the device from a known point on the card by a device such as a well known linear-displacement transformer such that the spatial arrangement of sensed concentrations may be decodedto yield identification of each of the characters on the card.

As shown schematically in the FIGURES, a mat of material or resilient pad 15 having, for example, reflective material suspended in a uniform density therein is compressed by a credit card 16. FIG. 1 shows the credit card 16 pressed against the face of the pad 15 and the areas of the pad adjacent the raised embossed decimal digits representing the identification, or account, number being compressed thereby. For details of the credit card and pad, see FIGS. 2 and 3.

Where, for example, light is the energy source (the light rays R in FIG. 3 showing such an embodiment with the light rays R striking the embossed account number) the light is reflected away where the embossed figures cause an increased concentration of light reflecting material to accumulate in the pad 15. An array of sensors 22a....22j are setin a frame or mask 20 spaced away from the pad and in position to sense the energy concentration of the material in the pad 15. The array of sensors are shown in a specific type of array in FIGS. 5 and 6, illustrated as circles l, 2, 3, 4 and 5, encompassing 10 sets or arrays of sensors 22a...22j; hereinafter disclosed, each of the [0 figures, decimal digits, or digit locations, on the face of the credit card 16 corresponding to a digit location on mask 20.

When the suspended material is not reflective but rather conductive, magnetic or radioactive, then the mask supports an array of sensors 22a...22j which are sensitive to the particular type of energy being used. It should be understood that in all embodiments, the circuitry is identical after the array of sensors 22a...22j, since the only difference in the various embodiments using different types of suspended material is the type of sensor, for example, with reflective material the sensors are photodetectors, with conductive material the sensors are current measuring sensors, with magnetic materials, the sensors are magnetic read heads" and with radioactive material the sensors are geiger-type sensors.

As stated, there is positioned a plurality or array of SCIISOIS 22a...2 2j by the mask 20. This array of sensors is identified all FIGURES by like reference numerals as are all the like parts in all the FIGURES.

While many differentkinds, or types, of sensors may be employed the type herein contemplated, for purpose of illustration,are: i

I. with reflective material-photodetectors such as the photoconductive device; e.g., a cadmium sulfide cell which has a very high resistance-in the absence of, or low intensity,

light and relatively low resistance in presence of light, or higher intensity light levels;

2. with magnetically affected material-sensors such as the "read head" device, e.g., a small coil in which a change in inductance will be effected by an increase in magnetic field strength due to the presence of a concentration of magnetic particles;

3. with conductive material-current measuring devices such as a small induction coil that will sense the presence of the conductive material through a change in the flux field of the coil; and

4. with radioactive material-Geiger devices which have an ability to sense the ionization caused by the presence of a radioactive material. Such devices are also sensitive to a change in level of radioactivity as a result of the concentration of particles as a result of compression of the pad.

As is described in more detail hereinafter each sensor 22a...22j location supported on the frame 20 has five apertures, or points, arranged in a unique array (all the arrays, or patterns, for the assumed l0 decimal digits or figures on the credit card being alike, however). In this respect, it has been discovered that the particular array herein employed is typical of many that enable recognition of all of the 10 decimal digits 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0, and other symbols which, for example, can have the form or font shown in FIG. 5.

As an illustrative example used herein such font has been chosen, more or less arbitrarily, for the instant example as the type font identified as IBM 1428 FONT, can be used as the coded form. However, the instant invention does not depend on the use of the aforementioned font or coded form. The general principle of the invention obtains in respect of recognizing, or reading, characters of any form embossed on the credit card and pressed against the pad 15 to increase the density of the suspended material by the embossment.

Referring again to FIGS. 1, 5 and 6, the mask 20 supports at each digit location the sensor unit array 22a...22j. In 0th. r words, at each digit location or figure, the mask 20 supports a sensor unit, or assembly, comprising five sensors or more particularly five photoconductors with or without filters, magnetic read heads, current sensitive devices, Geiger-type sensor or any combination of any of the aforementioned for capability ofa backup sensor to prevent error when one sensor of OI'IL system becomes defective, (see FIG. 4); one sensor being sup ported at each circle 1, 2, 3, 4 and 5 in the five sensor array at each area (digit location) on mask 20.

As shown, each sensor unit 'array 22a...22j is coupled through an individual amplifierunit generally designated in FIG. 1 by the reference number 24. From the amplifier units 24 signals generated by the sensors are fed to logic circuitry 26 which, as is more fully explained with reference to FIG. 4, processes the aforesaid signals and decodes the signals for the purpose of determining which one of the figures or decimal digits 0 through 9is being read. From the decoding logic circuitry 26 the signals are routed to an encoder 28 which encodes the output signals from the logic unit 26 into binary signals. The binary encoded signals are delivered via the paths 28a...28j to a comparator unit 30. Each path 28a...28j represents four or alternatively five channels for providing four or five binary signals, representing four or five binary bits respectively for the decimal numbers 0 through 0. Although the mask in FIGS. 5 and 6 and the logic circuitry of FIG. 4

used since more than one type of recognition pattern can be used with the embodiment of this invention. With four channels providing the signals, and with an account number having decimal digits, 40 binary digits, or bits, are delivered to a suitable register having 40 bit locations situated in the comparator unit 30.

Also, there can be provided amemory unit 32 which includes suitable storage means for storing 40 binary digits, or bits, for each account number which is considered to be a delinquent account, signifying a poor credit risk. As shown in FIG. 1 the 40 bits representative of a particular account number are delivered via the paths 32a... 32j from memory unit 32 to comparator unit 30. lf-all the bits delivered from the binary encoder 28 correspond with'all the bits delivered from the memory unit 32 then the. comparator unit 30 delivers an output signal identified as V,,,. The signal V 'may be used to drive a visible or audible alarm 34.

Shown at FIGS. 2, 3-and 3a of the drawings are illustrations of the kind of credit card herein employed in contact with the pad. in FIG. 2 the front face of the. credit card is shown and the decimal digits representing. the. account number appear thereon as indicated. The decimal'digits representing the account number are embossed in thezcard and in the view shown in FIG. 2 the embossed decimal. digits protrude outwards toward the observer. FIG. 3 with, which are cross sections through the credit card shown in. FIG. 2 with the account number embossed and etched, respectively, thereon, illustrate the foregoing more clearly. Forexample, as shown in FIG. 3 the embossed decimal digits are c'omprised'of a raised portion 164 on the front face of the card, and as shown in FIG. 3a, the etched decimal digits are corresponding cavity 16b on the reverse side of the card.

Also, as is indicated in FIG. 8, the pad is compressed bythe embossment so that the rays of'light are reflected from the compressed part of the pad 15 ofhigher density. The greater reflected light or redirected lightrays R are reflectedby a greater density of reflecting material. As a result the reflected rays R return a very large amount of light back through the transparent medium 14 of the pad '15".- Bycontrast, the rays of light which arereturned from the'noncompressed part of the pad 15 opposite the nonembossedface of the card 16are returned in a lesser quantity. With reflective material it should be understood that the pad must be manufactured from a transparent, resilient material. I

At FIG. 5 there is shown the type font employed for the 10' decimal digits 1, 2, 3, 4, 5, 6, 7,8, 9 and 0. As stated before, the type font employed herein is known as IBM 1428 FONT. In FIG. 5 there is superimposed "on each of the decimal digit locations 5 dotted circles which are representative of 5 sensors, supported by the mask shown in FIGS. 5 or 6. It is to be noted that the pattern of five sensors supported by the mask at each of the digit locations is a regular pattern. This is more clearly illustrated in FIG. 5 where the holes or dotted circles: are superimposed at each digit location. It is to be noted that for each of the ID digits the five sensor array pattern is uniquely superimposed on'each digit. In each five sensor array pattern one or more of the sensors maylieon the outside of the font representingathe digit- To illustrate this uniqueness more clearly, each sensor in the five array pattern which is identified by'reference numerals 1, 2, 3, 4 and 5 is described in conjunction with Table l, hereinafter appearing. If, for example, reference numeral 1 lies in superposition of the type font it is identified by the numeral '1. it, however, it lies outside of the type font it is represented by 1. The same is true for the reference numerals 2, 3,4 and 5. Of course it is to be understood that when any of the reference numerals 1 to 5- lie on the type font shown in FlGQS the reference numeral is directly opposite a compressed part. ofthe pad from an embossrnent of the credit card 16. if, however, thereference numeral lies outside, the type font of the pad 15 directly opposite is not compressed by the. embos'sment of the credit card 16. For example in FIG. 5 in digit 1 the reference numeral 1 lies opposite a compressed part of the pad 15 whereas in the digit 5 the reference number 1 lies opposite a relaxed area. Hence,

reference number 1 would be represented by 1 as far as digit 1 is concerned by as far as digit 5 is concerned it would be represented by the numeral 1. All this should become clear by Table l hereinafter appearing.

TABLE 1 Hole Decimal Digit 1 i s I 3 1 i 2 3 4 s z i i s 4 s s i 2 s i s 4 1 i s '4 s s 1 2 s I s s i 3 3 4 s 1 i z s 2 3 a l 5 s 4 s 9 I z s 4 s 0 Let it be'assumed that in FIG. 5 the decimal digits shown are compressing the pad 15 (not shown in FIG. 5). The array of sensors are shown on the mask 20L For the digit 6, as shown in Table 1 above, the sensor locations 1, 2, 3, 4, 5obtain and this represents the decimal digit 6. Similarly, decimal digit 4 is represented by I, 2, 3, 4, 5. Thus the bar represents a higher density while the absence of a bar represents a uniform density or that the bad 15 is relaxed opposite the sensor.

In FIG. 4-there is illustrated in block diagram form the logic circuitry 26 and the binary encoder 28 for a single digit position whereat a compression form only one digit onto the pad 15' obtains. As indicated in FIG. 5, five photodetectors 50, 51, 52, 53 and 54 are provided behind each of the reference numerals 1, 2, 3, 4'-and 5. .The sensors through 54 may be of the photoconductive read head," current reading or Geigertype. The sensors 50 through 54 are directly coupled to the amplifiers 32a through 32e.

As indicated in FIG. 4 each amplifier 32a through 32e is directly coupled to the input of an inverter 55 through 59, respectively. As indicated the output from the amplifier 32a is designated as'output 1 while the output from the inverter 55 is designated as the output 1. Likewise, the output from the amplifier 32b is designated as the output 2 while the output from the inverter56 is designated as output 2. Likewise, output from amplifier 32c is designated as 3 while the output from inverter 57 is designated as output 3. Also, output from the amplifier 32d is designated as output 4 while the output from the inverter 58 is designated as the output 4. Finally, the output from amplifier 32e is designated as the output 5 while the output from inverter 59 is designated as the output 5.

If, for example, reference numeral 2 is activated, the sensor 51 will drive the amplifier and inverter such that the output 2 appears-while the output 2 does not.

The outputs from the various amplifiers and inverters 1 or 1, 2 or 2, etcfiare used to drive the AND gates 60, 61,62, 63, 64, 65, 66, 67, 68 and 69. If, for example, the reference numerals and their associated sensors 50 through 54 were detecting the decimal signal 6 then the output from the amplifiers and inverters would be 1, 2, 3, 4, 5. Hence, the only AND gate to be driven would be the AND gate which would produce an output when all of its inputs were signals representing 1, 2, 3, 4 and 5.

The outputs from the AND gates 60 through 69 represent the decimal digits 1 through 0 respectively. These outputs are coupled to the OR gates 70, 71, 72 and 73. For example, the outputs from AND gates 60, 62, 64, 66 and 69 representing the decimal digits 1, 3, 5, 7 and 9 are fed as inputs to OR gate 70. The output from OR gate 70 delivers a weighted binary bit in the least significant bit position. The OR gates 70 through 73 represent the binary encoding portion of the circuit designated by the reference numeral 28 in FIG. 1. Similarly, the other decimal digit outputs from the various AND gates are indicated as driving the other OR gates 61, 62 and 63 in the manner shown.

In FIG. 7 there is shown an alternative embodiment of the invention when reflective material is suspended in the pad 15, employing an optical fiber system. As shown, against the face of the credit card 16 there is composed an array of optical fibers. More precisely, there is one optic fiber bundle designated as by the reference number 80 which brings light from light source to the face of the pad while another opti' cal fiber 80a returns the reflected light from the reflected material in the pad to the mask 20. Advantageously, it is seen that by using the scheme shown in FIG. 1 that the size as compared with the scheme shown in FIG. 7 may be greatly reduced in that the distance from the face of the card 16 to the mask 20 may be greatly shortened.

FIG. 8 shows a pad having a uniform density of suspended material therein and an embossed identification card concentrating the density of suspended material at the area of the compressments on the pad 15.

FIG. 9 shows an alternate arrangement wherein the pad 15 is a thin layered resilient sheet of uniform density made of material to which the sensors are able to sense a relatively thinner area, or the proximity of the raised material, due to stretching of the pad 15 at the embossments. A resilient pad 15a is disposed supportingly behind the pad 15 for support. In this embodiment the pad 15 can be a conducting, optical or other material in accordance with the above disclosure.

FIGS. 10 and l 1 show another alternate arrangement where the pad 15 has a resilient front face 15b shown distended in FIG. 10 and compressed by the embossments of an identification card 16 in FIG. 11. The pad 15 is hollow and contains a fluid 150 which is of uniform density. The thickness of the fluid 150 is sensed by the array of sensors 220 through 22j, shown in FIG.v l, in a manner described above with other embodiments. A reservoir 15d provides a sufficient amount of fluid 150 so that the fluid in the pad 15 is always filled. The reservoir 15d expands, as shown in FIG. 11, to accept excess fluid 15c forced from the pad 15 by the pressure exerted on the face of the pad 15 by the embossed identification card 16.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles involved, it is to be understood that the invention may be otherwise embodied without departing from the spirit and scope of the invention as hereinafter defined in the appended claims.

What I claim is:

l. A method of verifying the credit of a particular account wherein said account is evidenced by presentation of a credit card having thereon a plurality of embossed marks representing said account number comprising: a

a. pressing at least one of said marks against a resilient pad having a uniform density of suspended material therein in a reader;

b. sensing at a predetermined group of points in conformity with a preestablished code the density level of said suspended material at each of said points in the area 0 said pad compressed by each of said marks; I

c. generating sets of signals at each said group of points in response to the sensing of said density level, each generated set of signals being representative of an individual one of said marks;

d. encoding each set of generated signals in binary signal form; and

e. comparing said binary signals with other binary signals representing stored credit card account numbers in order to verify the credit of the account represented by the marks on said credit card.

2. The method as defined in claim 1, wherein the sets of signals generated in response to the sensing of density level at each set of points in the area of said pad represented in TABLE 1 in the foregoing specification.

3. The method as defined in claim 1, wherein said suspended material is a conducting material and said sensing material are electrical sensors.

4. The method as defined in claim 1, wherein said suspended material is a magnetic material and said sensing material are magnetic sensors.

5. The method as defined in claim 1, wherein said suspended material is reflective material and said sensing material are photoelectric sensors.

6. The method as defined in claim 1, wherein said suspended material is radioactive material and said sensing material are radioactive sensors.

7. A credit card reader comprising a resilient pad having a substantially uniform density of suspended material therein, at least one array of sensors spaced away from said pad, said sensors being sensitive to an increased density of suspended material at a position in said pad opposite each sensor in said array of sensors, first storing means for storing identification figures in a valid group, second storing means for storing identification figures in a nonvalid group, circuitry for comparing the output of said array of sensors as an identification figure identical with an identification figure pressed against said pad, and validation means for comparing said identification figure as one stored in said second storing means.

Po-ww UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,5963% l Dated July 1971 Inventor) William T. Tierney It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1 line 13 embossed in" should read --embossed on-- Column 1 line 7 "material of" should read ---material or Column L line 2 after identified the work --in-- is missing Column 4 line 72 o through 0" should read ---0 through 9-- Column 5 line 69 "pad 25" should read --pad 15-- Column 6 line 2 "by as far should read --but as far-- Column 6 line 30 'bad l5 should read --pad 15-- Signed and sealed this w th day of ."Maroh 1972.

(SALAL) Attes's:

EDLJ'ARD 1 "l.' '*lJElC5h3l ,.LQ, .wijlfilil GUTTSCIIALTL Attczzstlny; Officer Commissioner of Patents 

1. A method of verifying the credit of a particular account wherein said account is evidenced by presentation of a credit card having thereon a plurality of embossed marks representing said account number comprising: a. pressing at least one of said marks against a resilient pad having a uniform density of suspended material therein in a reader; b. sensing at a predetermined group of points in conformity with a preestablished code the density level of said suspended material at each of said points in the area of said pad compressed by each of said marks; c. generating sets of signals at each said group of points in response to the sensing of said density level, each generated set of signals being representative of an individual one of said marks; d. encoding each set of generated signals in binary signal form; and e. comparing said binary signals with other binary signals representing stored credit card account numbers in order to verify the credit of the account represented by the marks on said credit card.
 2. The method as defined in claim 1, wherein the sets of signals generated in response to the sensing of density level at each set of points in the area of said pad represented in TABLE I in the foregoing specification.
 3. The method as defined in claim 1, wherein said suspended material is a conducting material and said sensing material are electrical sensors.
 4. The method as defined in claim 1, wherein said suspended material is a magnetic material and said sensing material are magnetic sensors.
 5. The method as defined in claim 1, wherein said suspended material is reflective material and said sensing material are photoelectric sensors.
 6. The method as defined in claim 1, wherein said suspended material is radioactive material and said sensing material are radioactive sensors.
 7. A credit card reader comprising a resilient pad having a substantially uniform density of suspended material therein, at least one array of sensors spaced away from said pad, said sensors being sensitive to an increased density of suspended material at a position in said pad opposite each sensor in said array of sensors, first storing means for storing identification figures in a valid group, second storing means for storing identification figures in a nonvalid group, circuitry for comparing the output of said array of sensors as an identification figure identical with an identification figure pressed against said pad, and validation means for comparing said identification figure as one stored in said second storing means. 